[FFmpeg-devel] Using copyts with mpegts output fails after 26, 5 hours
When outputing to mpegts format, using -copyts option makes program
fail after the oveflow of mpegts PCR happens at around 26 hours and 30
minutes. When not using -copyts, only a warning is reported.
In order to reproduce the issue, you first have to create a 27 hour
mpegts video.
I have described the problem in thorough at ticket
https://trac.ffmpeg.org/ticket/7876
The issue is resolved if you use a patch created originally by Arut
(Roman Arutyunyan) at
https://github.com/arut/ffmpeg-patches/blob/master/mpegts-33bit
I have converted the patch in order to apply with current git and
confirmed working fine, fixing the above mentioned issue. Original
author describes the patch as: "Implements smooth 33-bit mpeg-ts
timestamp overflow in mpegts muxer."
Here it is:
--- libavformat/mpegts.c 2019-04-30 16:11:49.0 +0300
+++ libavformat/mpegts.c 2019-04-30 18:55:12.736428766 +0300
@@ -163,6 +163,9 @@
/** structure to keep track of Program->pids mapping */
unsigned int nb_prg;
struct Program *prg;
+
+/** base timestamp for smooth rolling over 33bits */
+int64_t base_ts;
int8_t crc_validity[NB_PID_MAX];
/** filters for various streams specified by PMT + for the PAT and PMT */
@@ -982,6 +985,26 @@
pkt->size = len;
}
+static int64_t unroll_timestamp(MpegTSContext *ts, int64_t t)
+{
+int64_t dt;
+
+if (t == AV_NOPTS_VALUE)
+return t;
+
+if (!ts->base_ts)
+ts->base_ts = t;
+
+dt = (t - ts->base_ts) & 0x01ll;
+if (dt & 0x01ll) {
+dt |= 0xll;
+}
+
+ts->base_ts += dt;
+
+return ts->base_ts;
+}
+
static int new_pes_packet(PESContext *pes, AVPacket *pkt)
{
uint8_t *sd;
@@ -1005,8 +1028,8 @@
pkt->stream_index = pes->sub_st->index;
else
pkt->stream_index = pes->st->index;
-pkt->pts = pes->pts;
-pkt->dts = pes->dts;
+pkt->pts = unroll_timestamp(pes->ts, pes->pts);
+pkt->dts = unroll_timestamp(pes->ts, pes->dts);
/* store position of first TS packet of this PES packet */
pkt->pos = pes->ts_packet_pos;
pkt->flags = pes->flags;
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Re: [FFmpeg-devel] Using copyts with mpegts output fails after 26, 5 hours
> On Thu, May 02, 2019 at 08:13:10PM +0300, Panagiotis Malakoudis wrote:
> > When outputing to mpegts format, using -copyts option makes program
> > fail after the oveflow of mpegts PCR happens at around 26 hours and 30
> > minutes. When not using -copyts, only a warning is reported.
> > In order to reproduce the issue, you first have to create a 27 hour
> > mpegts video.
> > I have described the problem in thorough at ticket
> > https://trac.ffmpeg.org/ticket/7876
> >
> > The issue is resolved if you use a patch created originally by Arut
> > (Roman Arutyunyan) at
> > https://github.com/arut/ffmpeg-patches/blob/master/mpegts-33bit
> >
> > I have converted the patch in order to apply with current git and
> > confirmed working fine, fixing the above mentioned issue. Original
> > author describes the patch as: "Implements smooth 33-bit mpeg-ts
> > timestamp overflow in mpegts muxer."
> >
> > Here it is:
> > --- libavformat/mpegts.c 2019-04-30 16:11:49.0 +0300
> > +++ libavformat/mpegts.c 2019-04-30 18:55:12.736428766 +0300
>
> doesnt apply with git am
> Applying: Using copyts with mpegts output fails after 26, 5 hours
> error: mpegts.c: does not exist in index
> Patch failed at 0001 Using copyts with mpegts output fails after 26, 5 hours
>
Sorry, it was a simple diff, not a git am compatible diff. Hope I made
it correctly this time:
From 5273daaf8e568fc2a2b9a77d91cb8a834b9e14e7 Mon Sep 17 00:00:00 2001
From: Panagiotis Malakoudis
Date: Thu, 2 May 2019 21:34:44 +0300
Subject: [PATCH] Implement smooth 33bit mpegts timestamp overflow in mpegts
muxer
---
libavformat/mpegts.c | 27 +--
1 file changed, 25 insertions(+), 2 deletions(-)
diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index 8a84e5cc19..b7f5d8ea4e 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -163,6 +163,9 @@ struct MpegTSContext {
/** structure to keep track of Program->pids mapping */
unsigned int nb_prg;
struct Program *prg;
+
+/** base timestamp for smooth rolling over 33bits */
+int64_t base_ts;
int8_t crc_validity[NB_PID_MAX];
/** filters for various streams specified by PMT + for the PAT and PMT */
@@ -982,6 +985,26 @@ static void new_data_packet(const uint8_t
*buffer, int len, AVPacket *pkt)
pkt->size = len;
}
+static int64_t unroll_timestamp(MpegTSContext *ts, int64_t t)
+{
+int64_t dt;
+
+if (t == AV_NOPTS_VALUE)
+return t;
+
+if (!ts->base_ts)
+ts->base_ts = t;
+
+dt = (t - ts->base_ts) & 0x01ll;
+if (dt & 0x01ll) {
+dt |= 0xll;
+}
+
+ts->base_ts += dt;
+
+return ts->base_ts;
+}
+
static int new_pes_packet(PESContext *pes, AVPacket *pkt)
{
uint8_t *sd;
@@ -1005,8 +1028,8 @@ static int new_pes_packet(PESContext *pes, AVPacket *pkt)
pkt->stream_index = pes->sub_st->index;
else
pkt->stream_index = pes->st->index;
-pkt->pts = pes->pts;
-pkt->dts = pes->dts;
+pkt->pts = unroll_timestamp(pes->ts, pes->pts);
+pkt->dts = unroll_timestamp(pes->ts, pes->dts);
/* store position of first TS packet of this PES packet */
pkt->pos = pes->ts_packet_pos;
pkt->flags = pes->flags;
--
2.20.1
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Re: [FFmpeg-devel] Using copyts with mpegts output fails after 26, 5 hours
OK, here it is again, attached. Στις Πέμ, 2 Μαΐ 2019 στις 9:56 μ.μ., ο/η Carl Eugen Hoyos έγραψε: > > Am Do., 2. Mai 2019 um 20:52 Uhr schrieb Panagiotis Malakoudis > : > > > > > On Thu, May 02, 2019 at 08:13:10PM +0300, Panagiotis Malakoudis wrote: > > > > > --- libavformat/mpegts.c 2019-04-30 16:11:49.0 +0300 > > > > +++ libavformat/mpegts.c 2019-04-30 18:55:12.736428766 +0300 > > > > > > doesnt apply with git am > > > Applying: Using copyts with mpegts output fails after 26, 5 hours > > > error: mpegts.c: does not exist in index > > > Patch failed at 0001 Using copyts with mpegts output fails after 26, 5 > > > hours > > > > > > > Sorry, it was a simple diff, not a git am compatible diff. Hope I made > > it correctly this time: > > You have to attach it to avoid linebreaks. > > Carl Eugen > ___ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". mpegts-33bit-git.patch Description: Binary data ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] Using copyts with mpegts output fails after 26, 5 hours
Στις Παρ, 3 Μαΐ 2019 στις 11:36 π.μ., ο/η Michael Niedermayer έγραψε: > > this will break timestamp handling > not sure what you are trying to do exactly but the way its done is wrong. > There is alot of code that depends on the timestamps from the demuxer > not being mangled like this. > > also its the wrong place, timestamp discontinuities are not a thing limited > to mpegts. And there are already layers of attempts to try to do what this > seems to try. Simple rule, if you dont need to allocate memory proportional > to duration in some cases then your code is wrong. Also if you dont intercept > seeks chapters and so on, again the code would be incomplete. > > If you want a specific testcase that this breaks. It breaks tbr values > amongth other things for > tickets/2186/multiple_programs.ts > > thanks As I mentioned in ticket http://trac.ffmpeg.org/ticket/7876 this is not my code, I just adapted it for current git. It is also very old code (back from 2012), probably it fitted OK back then. This code fixes this specific issue reported in the ticket. If it breaks other things, then of course it can't be commited. Still there is a need for a fix for the reported issue in the ticket, as it is you can't transcode with -copyts above 26,5 hours, it fails after that. > > [...] > > > -- > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > If you fake or manipulate statistics in a paper in physics you will never > get a job again. > If you fake or manipulate statistics in a paper in medicin you will get > a job for life at the pharma industry. > ___ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] fftools/ffmpeg: Disable copy_ts on timestamp wraparound
Στις Παρ, 3 Μαΐ 2019 στις 6:39 μ.μ., ο/η Michael Niedermayer έγραψε: > > This allows handling more than 26.5h of mpeg* input > > Fixes: Ticket 7876 > I confirm it fixes the case described in the ticket. Will now test it in realtime environment, so it will take 26,5 hours to report back. Thank you ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
